It is our goal to continue our molecular and genetic analysis of the cha-1 gene complex from the soil nematode Caenorhabditis elegans. cha-1 is the structural gene for choline acetyltransferase (ChAT), the enzyme which synthesizes the neurotransmitter acetylcholine. Previously obtained evidence suggests that the ChAT protein in C. elegans may consist of multiple structural and functional domains, and we are interested in determining the organization of the gene. In addition, ChAT is considered a differentiation-specific marker for cholinergic neurons, and we wish to investigate its spatial and temporal control during neural development. C. elegans is being used for these studies because of its simple nervous system, its ease of genetic analysis, and the availability of the technique of "transposon tagging" to clone genes from this organism. We have recently used the transposable element Tcl to "tag" and clone part of the cha-1 complex. A physical map of the gene will be constructed, and correlated with the genetic map already available. The complete nucleotide sequence of the gene will then be determined. Transcripts from the region will be studied by Northern analysis, S1 analysis, and the isolation of cDNA sequences. The transcriptional map thus constructed will be compared to the genetic map; this will test our published model of ChAT structure and function. The information obtained about wild-type gene structure and transcripts will then be used to analyze mutants defective in cholinergic function. Antibodies directed against ChAT will be produced, for use in biochemical and anatomical studies. Although this is basic research, it is clearly relevant to health, since alterations in acetylcholine metabolism and/or cholinergic function have been identified in many neurological and psychiatric disorders, including Alzheimer's disease, ALS, and depression.